Arthropoda and molluscs have open circulatory systems - meaning haemolymph (Their equivalent to blood) directly bathes the tissue, and isn't enclosed in blood vessels, as seen in a closed blood system, as in humans for example.
Answer:
About 5billion years ago is the correct option.
Explanation:
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B) cortisol ensures that the brain has glucose when it’s necessary. Cortisol is a steroid hormone that helps control blood sugar levels, metabolism, and inflammation. Glucose, also known as sugar, is an energy source used in cells in the body. The brain is highly demanding of energy since it is so rich in nerve cells and neurons, so glucose is essential to the brain. Too much can harm the brain though, so it is important for the cortisol to control the sugar levels.
